We study the conditions under which members of Congress incorporate policy‐specific considerations in their decisions. To do this, we estimate a model that accounts for the influence of private information about legislation quality on voting patterns in the House and Senate. We find that minority party members are more likely to evaluate proposals on their merits than majority members, but institutional and electoral considerations significantly attenuate these partisan differences. In particular, seniority, electoral safety, and constituents' political knowledge have a balancing effect on partisan predispositions to rely on policy‐relevant information, making minority (majority) members less (more) likely to vote informatively.